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Discussion Starter · #1 ·
So recently I noticed that my engine felt a little rougher at idle, like it might have am occasional misfire.
Then the other day I noticed that every so often when coming to idle from high speed the revs were hunting, from 500 to 1000 rpm.
Today the engine gave me an EML light.
It drives OK, although still feels a little lumpy.
I popped the bonnet and disconnected the MAF, which made little difference, but when I reconnected it the revs started hunting again. Then they either settled or the car stalled. I also noticed that my Disa is rattling.
Any thoughts? My disa is on the way out but is that the cause of the rough running and EML?
I know two out of 6 coil packs are old and will need replacing soon. Is this a symptom if that?
 

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There is also a fair chance the Idle Control Valve is dirty/sticking/jammed, easy enough to clean it.

If you know the DISA valve is „on its way out?“ then it would be prudent to either replace it or buy one of the repair kits from the internet (letting the DISA valve break can in very rare cases cause severe engine damage).
When you are getting your hands dirty then giving the Throttle Body a good clean is also „Not going to make the situation worse“.

But before you start anything test for a vacum leak on the air intake boots and attachments (spray can of brake cleaner if leaking the engine will increase in revs).
 

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Discussion Starter · #4 ·
I don't want to replace the Disa right now if I don't have to. I've had a few big bills recently and money is tight. Just want to find the cause of the EML light really.
Disa is on the list, a long list...
ICV clean is easy so I'll give that a go.
I could really do with a fault code reader.
 

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If your intake boots are old (believe your car is a 2004?) then be aware that they might be damaged when removing to gain access to the ICV ( not expensive and if they crack it’s really inconvenient).
 

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Discussion Starter · #6 ·
I've had the whole lot off recently to do the CCV and they were in pretty good condition. Can't help thinking that I've disturbed/damaged something...
 

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Rough idling is usually caused by a vacuum leak. Check all your intake pipes and any hozes to/from the manifold for splits/cracks etc.
If you can't see anything obvious, it might be worth doing a smoke test. Advice about taking off and cleaning the ICV is also a good idea.
A loose DISA valve flap won't cause idling problems however if it falls out and breaks up inside the intake it could trash your engine so I would at the very least try to repair it if possible. It's not a difficult or expensive job and it could save your engine.
 

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A broken DISA valve ie. The flap is no longer attached to the shaft can stop your car from idling! I had my DISA flap go ( I am sure it was the carousel on the nüby Ring, but once off the car struggled to run unless loads of throttle) I drove home about 250kms and when home Googled and thought jeez „What if“?
I had NO Eml light with that fault! but defo the car struggled to run at idle.
 

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Discussion Starter · #10 ·
I'll have to have a good look at the intake system.
I also want to get the codes read.
I will check out the Disa valve repair kits. It's just a bit noisy at the moment.
 

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Just for interest @dr evil I replaced my Coil Packs (X6 ) last week for Delphi Industrie ones they cost 21.60 GBpounds a piece and cured my misfire problem, (oem pt number 12138616153) plus Bosch Platinum 4 spark plugs even though my BERU ones were not old. It’s a long game:).

Getting a code reader (ie.INPA and a d/k can cable) can make your life easier but it will not give every answer ( you have too Be able to process the info logically, and it is not easy!). But it’s a good Start (y)
 

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Many years ago...

I can confirm, loose disa disturb idle rpm. I was standing front of traffic lights. Engine acting weird not stable rpm. But is was easy fix, as you can hear disa not working proper.

It was a Vaico disa (preventive maintenance), waste of money...
So I put back 19 years old disa😃 in waiting of upgrade kit.
 

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Discussion Starter · #14 ·
Checked fault codes
E3 Fuel trim bank 1, permissable range exceeded.
08 Signal, air mass flow sensor.

Now I ran the engine with the air mass flow sensor disconnected so that might be the cause of the 2nd fault.
Going to run car again tomorrow and see which ones come back.
Also going to check disa valve.
 

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Vaico disa failed at pivot link (broken - cheap pllastic used). Oem still going strong with upgrade kit.
 

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Discussion Starter · #16 ·
Intake boot split.
Disa working but not great.
I will replace the boot and look at refurbishing the Disa. Replacement diaphragm isn't included in any of the repair kits for some reason and there is one online seller who is charging £12 and £9 postage for a tiny bit of rubber.
 

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Discussion Starter · #19 ·
Diaphragm was fine...but in the process of checking I managed to break the housing 🤬
So now it most definitely is not fine.
🤬🤬🤬🤬🤬🤬
 
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